[jira] [Commented] (AMBARI-18569) Execute topology tasks in parallel by hosts

["Hadoop QA (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/AMBARI-18569?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15648737#comment-15648737 ] 

Hadoop QA commented on AMBARI-18569:
------------------------------------

{color:red}-1 overall{color}.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12838005/AMBARI-18569.patch
  against trunk revision .

    {color:green}+1 @author{color}.  The patch does not contain any @author tags.

    {color:red}-1 tests included{color}.  The patch doesn't appear to include any new or modified tests.
                        Please justify why no new tests are needed for this patch.
                        Also please list what manual steps were performed to verify this patch.

    {color:green}+1 javac{color}.  The applied patch does not increase the total number of javac compiler warnings.

    {color:green}+1 release audit{color}.  The applied patch does not increase the total number of release audit warnings.

    {color:red}-1 core tests{color}.  The patch failed these unit tests in ambari-server:

                  org.apache.ambari.server.configuration.ConfigurationTest

Test results: https://builds.apache.org/job/Ambari-trunk-test-patch/9182//testReport/
Console output: https://builds.apache.org/job/Ambari-trunk-test-patch/9182//console

This message is automatically generated.

> Execute topology tasks in parallel by hosts
> -------------------------------------------
>
>                 Key: AMBARI-18569
>                 URL: https://issues.apache.org/jira/browse/AMBARI-18569
>             Project: Ambari
>          Issue Type: Task
>          Components: ambari-server
>    Affects Versions: 2.4.0
>            Reporter: Doroszlai, Attila
>            Assignee: Doroszlai, Attila
>             Fix For: 3.0.0, 2.5.0
>
>         Attachments: AMBARI-18569.patch
>
>
> Currently when a cluster is created using Blueprints, {{PersistHostResourcesTask}}, {{RegisterWithConfigGroupTask}}, {{InstallHostTask}} and {{StartHostTask}} topology tasks are created in this order for each host. These tasks are then executed by a single-threaded executor {{TopologyManager.executor}} as hosts are being assigned to the cluster.
> Since {{TopologyManager}} is singleton, this leads to sequential execution of topology tasks on a single thread. The execution of the each individual topology task involves db operations under the hood. If for any reason there is some latency introduced by the db operations (e.g. the db server is remote instead of local) than this latency builds up a considerable delay if there are many hosts to execute topology tasks for.  Executing the topology tasks in parallel would reduce the delay in this case.
> Topology tasks for a host must be executed in order, but tasks that belong to different hosts can be executed concurrently.  E.g. the  {{PersistHostResourcesTask}}, {{RegisterWithConfigGroupTask}}, {{InstallHostTask}} and {{StartHostTask}} topology tasks would be executed sequentially by one thread for host1 and by another thread for host2.



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